DirectAdmin Roundcube Branding: Custom Webmail URL

DirectAdmin ships Roundcube through CustomBuild, currently at 1.7.4, and exposes it under /roundcube on every hosted domain as well as on the panel hostname. Providers usually want three things beyond the default: a clean webmail.customer-domain address, a logo and product name that match their brand, and a webmail link in the panel that logs the user straight in. All three are supported without patching Roundcube, provided the customisations live in the places CustomBuild preserves.

Short answer: Set Roundcube as the CustomBuild webmail client with da build set roundcube yes and rewrite the configuration so webmail. subdomains land on it, then set webmail_link and one_click_webmail_link with da config-set for the panel button. Put a copy of config.inc.php containing product_name, skin_logo and support_url under custombuild/custom/roundcube/ so the branding survives every da build roundcube.

The webmail subdomain

CustomBuild’s web-server templates already include a virtual host for webmail. on every domain, alongside mail., and DirectAdmin adds the matching A record to new zones. The template variable that controls the target is the webmail choice in CustomBuild; set it to Roundcube and rebuild the configuration if the subdomain currently lands on a different client or on the domain’s own document root:

da build set roundcube yes
da build roundcube
da build rewrite_confs

Existing zones that predate the setting lack the webmail record. Add it to the DNS template so new domains get it, and to existing zones in bulk:

grep -L '^webmail' /var/named/*.db
echo "action=rewrite&value=named" >> /usr/local/directadmin/data/task.queue

Because the new ACME TLS system issues certificates per domain with up to 25 names, webmail. and mail. are included automatically for domains that opted in, so the subdomain serves a valid certificate. Domains still on manual certificates need the name included by hand.

The one-click login link

1.688 introduced one_click_webmail_link. When enabled, the webmail button in the Evolution email pages opens Roundcube with a short-lived token instead of asking the user for the mailbox password again:

da config-set one_click_webmail_link 1

Since 1.710 da config-set reloads the panel automatically. The feature relies on the panel and Roundcube sharing the same hostname or the webmail_link setting pointing at a Roundcube instance the panel trusts; if the link opens the login form instead of the inbox, check that webmail_link matches the URL the browser is actually redirected to.

Where a provider hosts one branded webmail address for all customers, set the panel’s link to it:

da config-set webmail_link https://webmail.provider.example/

Branding without losing it on rebuild

Roundcube’s files live in /var/www/html/roundcube, and da build roundcube replaces them on every version bump. Anything edited in place is lost. CustomBuild reads overrides from its custom directory instead:

mkdir -p /usr/local/directadmin/custombuild/custom/roundcube
cp /var/www/html/roundcube/config/config.inc.php /usr/local/directadmin/custombuild/custom/roundcube/config.inc.php

Edit the copy. The settings that carry the branding are product_name, skin_logo and support_url; skin_logo accepts a path relative to the Roundcube root or an absolute URL:

$config['product_name'] = 'Provider Webmail';
$config['skin_logo'] = 'https://webmail.provider.example/branding/logo.svg';
$config['support_url'] = 'https://provider.example/support/';
$config['login_lc'] = 2;

For a custom skin, place it under custombuild/custom/roundcube/skins/ and reference it with $config['skin']. CustomBuild copies the custom directory over the fresh install at the end of each build, so the skin and config survive. Check the CustomBuild changelog for your version if the path layout differs; the custom/roundcube behaviour has been stable for several years but the list of files copied has grown.

Rebuild once to confirm the override is applied:

da build roundcube
grep product_name /var/www/html/roundcube/config/config.inc.php

Common pitfall: hard-coding the database or des_key

Copying the whole config.inc.php into custom/ freezes values that CustomBuild normally generates, notably the database password and des_key. If the Roundcube database password is later rotated, the override still carries the old one and webmail fails with a database error. Either keep only the branding lines in the custom file and let CustomBuild merge the rest, which recent versions support, or remember to update the override whenever credentials change. The Roundcube database error guide covers the symptom, and the fix is the same on DirectAdmin.

Verify

Open https://webmail.example.com/ for a hosted domain and confirm the logo, product name and a valid certificate. From the shell, check the virtual host resolved to Roundcube rather than the domain’s document root:

curl -sI https://webmail.example.com/ | grep -i -E 'location|server'
curl -s https://webmail.example.com/ | grep -o '<title>[^<]*'

Then log into the panel as a user, open the email accounts page and use the webmail button; with one_click_webmail_link enabled the inbox should open without a second password prompt. Repeat after the next da build roundcube to confirm the branding persists.

DirectAdmin Roundcube branding at a glance

Official documentation: DirectAdmin documentation, RFC 5321 (SMTP), Linux man pages.

Related guides: Choosing a VPS for a cPanel or DirectAdmin server in 2026 · Exim 4.99/4.100 on cPanel and DirectAdmin: the 2026 security fixes and what changed for admins · DirectAdmin mail delivery problems: forwarder loops, send-limit counting and outbound MX lookups.

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